Introducing Let's Seal
Today we're releasing the first project from Experimental Open Works: Let's Seal.
Let's Seal is a free way to cryptographically seal PDF documents. It is an open alternative to the closed, paid trust programs — like the Adobe Approved Trust List — that quietly decide whose signatures software will accept and whose it will flag.
The problem
When you seal a document, the value comes from other software recognising that seal. Today, that recognition is gated. To be trusted by default in the tools most people use, a certificate authority has to buy its way onto a private list, and those costs get passed down. The result is a small toll booth sitting on top of something that should be open infrastructure.
We think trust should be inspectable, not purchased.
What Let's Seal does
- Seals PDFs cryptographically, so anyone can verify a document hasn't changed since it was sealed.
- Is completely free — no account, no paid tier, no per-document fee.
- Is open source, so you can read exactly how it works before you rely on it.
Let's Seal is named in the spirit of Let's Encrypt, which made TLS certificates free and, in doing so, encrypted most of the web. We'd like to do the same thing for document seals.
What it is not
We want to be careful here. Let's Seal is a tool for sealing and verifying documents. It is not a notary, it does not verify anyone's legal identity, and it makes no claim about whether a given signature is legally binding in your jurisdiction. Those are separate questions, and we won't pretend otherwise.
Try it at letsseal.org. If you find a rough edge, tell us — it's early, and it's yours as much as ours.